There has been conventionally known an applicator that makes an impact on a microneedle array administering an active agent through a skin so as to apply microneedles included in the microneedle array to the skin.
For example, the following Patent Literature 1 discloses an applicator that includes a device body, a piston for impacting a penetrating member with a stratum corneum, an impact spring for providing an impact force to the piston, a hold down spring operating between the device body and a cap, and a lock mechanism for compressing the device body and the piston together with compressing force so as to cock and lock the piston in a cocked position.
The following Patent Literature 2 discloses an applicator that includes a housing, a piston movable within the housing, and a cap.
The following Patent Literature 3 discloses an insertion device for applying an insertion head that includes an infusion cannula or a puncturing tip introduced into a body of a patient. The device includes two actuation members, which have to be actuated simultaneously to trigger the insertion movement.
The following Patent Literature 4 discloses a puncture device including a drive spring in which one end of the drive spring is not fixed to a housing side contact section or a piston.